08-15-2023, 07:31 PM | #1 |
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8HP45 Swap to 8HP50
Im posting here because I’ve had no luck getting replies on my last 3-4 posts in the diesel forum. I’ve even tried posting on Reddit but got no replies there either.
Car: 2014 328d with stage 2 engine and transmission tune. 135k miles. Owned since 30k miles. Tuned since 75-80k miles. Issue: my transmission is going. More specifically the torque converter. I have a nasty grinding scraping sound that doesn’t change with speed. I have an opportunity to buy a 8hp50 transmission with only 3k miles. I like the idea of replacing the 45 with the 8hp50 bc it holds +50nm more. It should be plug n play, but I am planning on swapping the mechatronics to avoid having to clear the INS with ISTA but more importantly not to lose my custom tranny tune. FYI it’s not xHP. Couple things I’m not sure about with the swap. 1 - I read that the gear ratios are slightly higher in the 50 as compared to the 45. My understanding is that ZF did this for emissions purposes. Can I assume the mechatronics are identical between the 45 and the 50? Will there be any issue with the difference in gear ratios? Hoping it’s not noticeable or the tranny just “learn” and adapt to it. Ideally I’d like to just pull the tranny, swap the mechatronics, install new trans, flush fluid, and be done. The tranny that I’m planning on buying comes from a M340i. So I believe I will need to buy a flex disc/flywheel for a B58. Either that or fit a torque converter to the tranny but that doesn’t make sense going that option. I plan on grabbing one from eBay or a junkyard. Am I missing anything? This seems very doable. Originally I was planning on doing this but swapping in a 8hp70. However, I read a few posts where some people attempted a 8hp70 swap but could never get it to shift right. Maybe software wasn’t available at the time. That and this 8hp50 transmission only has 3k miles on it for a fair price Any thoughts? Suggestions? Forgot to mention that I was getting shudder or slippage when hitting it hard in 5th gear. I barely get on it but I think that was enough to cause it to self destruct over the last year. I have videos of the noise if anyone is interested. |
08-19-2023, 10:27 AM | #2 |
@_sunbish
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Compare the Bellhousings and let me know what you think.
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'14 435i RWD - BM3 stage 2+ E30/bolt ons/stock turbo/full drag pack -- [10.9@125].....60 to 130 - 8.5
'16 340i RWD - BM3 stage 2+ E50/bolt ons/stock turbo/full drag pack -- [10.2@131]......60 to 130 - 7.5 |
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08-21-2023, 07:48 PM | #4 |
@_sunbish
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It's worth a shot, but honestly it isn't much of an upgrade.
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'14 435i RWD - BM3 stage 2+ E30/bolt ons/stock turbo/full drag pack -- [10.9@125].....60 to 130 - 8.5
'16 340i RWD - BM3 stage 2+ E50/bolt ons/stock turbo/full drag pack -- [10.2@131]......60 to 130 - 7.5 |
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12-23-2023, 10:56 PM | #6 | |
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Quote:
I ended up changing my tranny fluid which was burnt to hell and about 1.5 quarts low. Prob burned up. Drive fantastic initially. Then it started making noise again. I drove it hard one day and it’s been great since. Prob been like 1,500 miles now. I know I still need at least a new torque converter or a whole tranny. It’s hard to find a low mileage tranny. There’s a place in Old Saybrook, CT, Erikkson Industries, that will remanufactorer your torque converter for $385. They will do it via shipping too if you aren’t local. I will probably pick up a low mileage 8hp45 tranny from a gasser/petrol and have my torque converter rebuilt by them. |
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Polo088161614.50 |
12-25-2023, 07:25 AM | #7 | |
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I think that's why I will eventually transition to domestic vehicles like the 7th Gen Mustang Dark Horse or the C8 Z51 to keep catastrophic powertrain failure costs down. |
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